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Cellular Respiration

cellular respiration - oxidation of organic molecules, release of energy

  • C6H12O6 + 6O2 >> 6 CO2 + 6H2O + ATP + heat
  • usually organic molecules taken in, CO2/H2O released as waste
  • adenosine triphosphate (ATP) - used as direct source of energy in cellular metabolism
  • glycolysis - oxidation of glucose to pyruvate
    • some energy stored in ATP
    • occurs w/ or w/o oxygen, but doesn't continue to citric acid cycle w/o oxygen
  • citric acid cycle (tricarboxylic acid cycle or Krebs cycle)
    • oxidizes pyruvate to CO2
    • must use oxygen
    • used by aerobes
    • stores energy in nicotinamide adenine dinucleotide (NAD)
  • electron transport chain - makes proton gradients from energy in NAD
    • makes about 18x as much ATP as glycolysis
    • oxygen - final electron acceptor; chain won't work w/o oxygen
    • measuring O2 consumption/ CO2 production also measures the aerobic respiration rate

anaerobes - live w/o oxygen; may even be poisoned by oxygen

  • use inorganic electron acceptors
  • uses fermentation instead of Krebs cycle to reduce pyruvate
    • makes ethanol in plants/yeast
    • makes lactic acid in animals
  • C6H12O6>> 2C2H5OH (ethanol) + 2CO2 + ATP + heat
  • C6H12O6>> 2CH3CHOHCOOH + ATP + heat
  • produces 18 fewer ATP than aerobic respiration
  • pickling - preserves food, involves anaerobic fermentation of sugars to lactic acid
  • wine making - invovles alcoholic fermentation by yeasts
Subject: 
Biology
Subject X2: 
Biology

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